1. Field of the Invention
The present invention relates to injectable compositions having primary utility for soft tissue augmentation.
2. Related Background
Over the years, many attempts have been made to develop injectable compositions for soft tissue augmentation, especially breast augmentation. Although in recent years the emphasis in breast augmentation has been on surgically implantable breast prostheses, injectable compositions offer the very important advantage of being able to avoid a surgical procedure.
Some of the early attempts to make injectable compositions for breast augmentation involved the use of silicone gel. However, silicone injected subcutaneously has a tendency to migrate into the surrounding tissue causing, among other problems, granulomas. Accordingly, injectable liquid gels are no longer in use.
Subsequently, injectable collagen in suspension became the composition of choice. However, natural collagen has a great tendency to be resorbed. Therefore, in order to have soft tissue augmentation that did not dissipate shortly after injection, it was found necessary to cross link the collagen with agents such as glutaraldehyde. Cross linking inhibits resorption. However, recently the use of glutaraldehyde cross linked collagen has itself come under attack.